Field of the Invention
The present invention generally relates to sealing of a bearing, and more particularly, to a sealing device for the bearing and a mounting method of a sealing plate for a bearing.
In a conventional sealing plate for a bearing, a core metal formed by punching a metallic plate is placed in a recess or concave portion of a metal mold for molding by pouring an elastic material therein, and the bearing sealing plate formed thereby is so adapted that its forward edge diameter is slightly larger than an opening diameter of a bearing sealing groove, and a wall face of the sealing groove of an outer race or inner race of the bearing is sunken so as to force the bearing sealing plate into the sealing groove, thus causing the forward edge portion of the sealing plate to depress the wall face of the sealing groove to achieve the sealing.
In the known bearing sealing plate as described above, there have been disadvantages in that, since the bearing sealing plate is molded by pouring an elastic material into a metal mold and the constructions and shapes of the sealing plate and the bearing sealing groove are complicated. Thus, many steps are needed in the manufacture (for example, in the preparation of the metal mold or removal of burr after the molding, etc.) and these require much time and expense, with a consequent rise in cost.
Meanwhile, miniaturization of various products is now under way, and following such a trend, reduction of the bearing size has been still more strongly demanded. Thus, a bearing sealing plate which can be accommodated in a much smaller space is required. However, in small sized bearings, the sealing groove must be reduced in its diameter, thus making it difficult to be efficiently processed. Also, especially in the case of a deep sealing groove there is another problem in that the strength of the outer race or inner race is undesirably lowered.
Moreover, in the case where the bearing sealing plate is made of a metallic material, proper performance of the sealing plate tends to be obstructed through deformation of the bearing outer race or inner race, with a possibility of leakage of grease from the outer circumferential portion of the bearing sealing plate.